Various synthetic polymer latices derived from acrylic esters can be made self-curing. That is, they are capable of being cured at elevated temperatures without the necessity of adding curing agents externally. These acrylic ester polymers are useful for many applications where articles, such as nonwoven fabrics, textiles, papers, or other substrates, are coated, impregnated, or otherwise saturated with an aqueous dispersion of the polymer. These latices contain reactivity in the polymer obtained by the polymerization of a minor proportion of one or more reactive monomoers with the acrylic ester monomer. These self-compositions, capable of being cured by heat, have a long shelf life in the uncured state.
However, one disadvantage of these self-curing compositions is that they must necessarily be heated at temperatures of about 300.degree. F. or 325.degree. F. to obtain acceptable cures and optimum physical properties. It would be advantageous to have articles, such as nonwovens, textiles, and paper treated with self-curing polymer latices which are capable of being cured at temperatures below about 300.degree. F. to obtain optimum or near optimum physical properties with minimum discoloration and with good heat sealability to enable the fabrication of finished articles cheaply, that is, without expensive stitching and like operations. These articles could be produced at much faster rates and more economically due to lower heat requirements.
It would be highly advantageous to obtain vinyl halide and vinylidene halide polymer latices which are self-curing and capable of being heat sealed after curing. Heretofore, it has been difficult to introduce the necessary reactivity into vinyl halide and vinylidene halide polymers since the reactive monomers conventionally employed are not, under the usual emulsion polymerization conditions, compatible with the polymerization of vinyl halide or vinylidene halide. This is due to the markedly different reactivity ratio of these reactive monomers to that of the vinyl halide and vinylidene halide monomers. Introducing such reactive monomers with vinyl chloride, for example, would normally shortstop the polymerization or at least inhibit the polymerization so as to make it impracticable.
In the case of acrylate and nitrile latices the self-curing mechanism is incorporated by copolymerizing an .alpha..beta. -olefinically unsaturated carboxylic acid and an olefinically unsaturated amide or its N-alkylol derivatives with the acrylate or nitrile. However, the amide derivatives do not readily copolymerize with vinyl and vinylidene halides. It would be advantageous to incorporate such a curing mechanism in vinyl halide and vinylidene halide polymers because such polymers would make superior heat seal adhesives for use in substrates, particularly in the automotive industry, since they are harder polymers.